Scientists Achieve a Rare Form of Superconductivity on Silicon

Researchers at the University of Tennessee have shown that silicon can serve as a host for chiral superconductivity. The quest for a superconducting silicon chip is an important goal for material scientists.

Today's superconductors are extremely expensive and temperamental, requiring low temperatures and careful handling. Hosting superconductivity on a silicon chip could prove revolutionary for several high tech fields, including quantum computing.

Chiral superconductivity is a quantum mechanical phenomenon that relates to the angular momentum of electrons.

According to the story at Physics.org, "In chiral systems, clockwise and counterclockwise rotations are the same and yet different – like how left and right hands are mirror images of each other that can't be superimposed. In quantum mechanics, the properties of single or paired electrons are encoded in a mathematical wavefunction that can be left-handed, right-handed, or 'topologically trivial.'"

Professors Hanno Weitering and Steve Johnston, along with colleagues in the US, Spain, and China, "replicated cuprate-like physics by growing one-third of a monolayer of tin atoms on a substrate (base layer) of silicon. Think of it as nine silicon atoms in a single layer, with three tin atoms – placed farther apart – stacked in another layer on top. The system is engineered such that the repulsion between the tin electrons is so strong they can't move and won’t superconduct. Weitering, Johnston, et al., found a clever workaround by implanting boron atoms in the silicon layer's diamond-like crystal structure. The boron atoms proceeded to steal electrons from the tin layer (typically about 10 percent) in a process similar to techniques perfected by the semiconductor industry."